1. Field of the Invention
The present invention relates to a dielectric ceramic composition of MgTiO.sub.3 -CaTiO.sub.3 group for microwave application and a dielectric ceramic fabrication method using the same, and in particular, to an improved dielectric ceramic composition of MgTiO.sub.3 -CaTiO.sub.3 group and a dielectric ceramic fabrication method using the same which are used for passive components in microwave range and have a high quality factor and an excellent temperature stability.
2. Description of the Conventional Art
As various communication devices are advanced, the products adapting such devices are made to have a high quality and to be compact. In order to meet these trends, various components for an information communication device are required to have a high quality and to be compact. Therefore, a demand for a new material having better properties as well as good design of the components is increased. In particular, since it is expected that the development of the passive part such as a band pass filter or duplexer using a dielectric ceramic meets the demand for a compact and low electric power consumption and high performed product, the research and development for various dielectric ceramic materials having such excellent characteristics have been widely developed.
The MgTiO.sub.3 -CaTiO.sub.3 compound is a dielectric ceramic capable of variably controlling a dielectric characteristic depending on the composition ratio of two components. A method is known to add various additives to the dielectric ceramic for controlling a dielectric characteristic and a sintering characteristic (for example, U.S. Pat. Ser. No. 5,340,784 and U.S. Pat. Ser. No. 4,242,213). The method is known to add some oxide materials or to substitute an element of a lanthanum series with Ca for thereby enhancing a dielectric characteristic of the dielectric. As a result, it is possible to obtain a dielectric material having a dielectric constant .epsilon..sub.r of about 20 and a temperature coefficient of resonant frequency .tau..sub.f of within .+-.10 ppm/.degree. C. However, in view of the quality factor Q and sintering temperature, it is impossible to obtain a desired result.
Generally, the dielectric ceramic materials should have a high dielectric constant and quality factor and a stable temperature characteristic. In order to obtain the above-described material characteristic, a new additive is required to be added, and also controlling the microstructure and improvement of the fabrication processes are necessary.